Endocrine Abstracts

Pituitary apoplexy (PA) is a rare clinical syndrome due to sudden haemorrhage and/or infarction of the pituitary gland, usually within a pre-existent pituitary tumour. Even though some sporadic cases of PA associated with rare sellar lesions (such as Rathke cleft cysts) have been reported, in the vast majority of cases the syndrome occurs within a pituitary adenoma. At presentation, patients with PA usually complain of sudden and severe headache, often associated with visual loss or ocular palsy. Arterial hypertension, major surgery, anticoagulant therapy, angiography, dynamic tests, dopamine-agonists, GnRH agonists have been advocated as possible precipitating factors. However, they may be identified in a minority of cases altogether (10–40%). The pathophysiology of PA has not been completely clarified. Interestingly, imaging studies, surgical exploration and histopatological analysis may identify both haemorrhage and ischemic necrosis, but all these procedures cannot always clarify the first step that has triggered the dangerous cascade of events. There is evidence that some unpredictable cardiovascular events, such as acute myocardial infarction and stroke, often occur early in the morning. In order to verify whether a circadian pattern in the occurrence of PA may exist, we conducted a retrospective analysis in a cohort of patients who presented with signs and symptoms of acute PA. Twenty-five patients with PA were excluded because of the lack of information about the time of occurrence of the syndrome. A total of 60 patients with PA who referred to our centre during the last two decades were included in the study. Of these, 24 (40%) showed the first signs and symptoms of PA in the morning (6 a.m. to 12 a.m.), 12 (20%) in the afternoon (12 a.m. to 18 p.m.), 13 (20.6%) in the evening (18 p.m. to 24 p.m.), and 11 (18.3%) during the night (0 p.m. to 6 a.m.). The tumour associated with PA was a non-functioning pituitary adenoma in 41 cases (68.3%), a PRL-secreting adenoma in 12 cases (20%), an ACTH-secreting adenoma in 4 cases (6.6%), and a GH-secreting adenoma in 3 cases (5%). In conclusion, our data suggest that PA occurs more frequently during the morning hours. To the best of our knowledge, our study represents the first demonstration of circadian variation in the the occurrence of PA.